In order to carry out biochemical studies of certain compounds such as 5-[3-(2-(7-chloroquinolin-2-yl)-ethenyl)phenyl]-8-dimethylcarbamyl-4,6-dit hiooctanoic acid (also known as L-660,711) a potent antagonist of leukotriene D4(LTD.sub.4) on the LTD.sub.4 receptor, it is desirable to prepare the antagonist with high intrinsic radioactivity. The introduction of a .sup.35 S atom appears to be an attractive way to fulfilling this requirement. Prior art compounds such as C.sub.6 H.sub.5 CH.sub.2.sup.35 SH described by Gemeiner et al in Chem. Abs. 86: 157295Y(1977), 99: 7012h(1983), 100 193798f (1984) or those of the formula; O.sub.2 N--C.sub.6 H.sub.5 --CH.sub.2.sup.35 SH described by Watabe et al in Chem. Abs. 103, 191021K are difficult to use for this purpose because they are more difficult to de-block.
H.sub.2.sup.35 S has also been used as starting materials for introducing a sulfur radioisotope into same molecules. However, it being gaseous, is hazardous and difficult to use. In addition, it suffers from the drawback of having two reactive hydrogens which can cause problems in small scale reactions.
As to the method of preparation, Boscato et al described methods for the incorporation of elemental sulfur into organic compounds. See Tetrahedron Letters 21 1519 1520 (1980). The reaction may be represented by the scheme: ##STR1##